The prevalence and incidence of obesity is increasing dramatically either in developed or the developing country, and the age of patients suffering from obesity tended to be younger, it has been becoming a global epidemic of serious health effects. Obesity not only affect the daily life, induce psychological problem, and probably social discrimination; the most serious consequences is that obesity cause many diseases, such as type 2 diabetes, coronary heart diseases, hypertension, hyperlipidemia, cholecystitis, arthritis and some cancers, about 80% obesity combined one and 40% obesity combined two diseases mentioned above (Xu Manyin editor, diabetes, second edition, Shanghai science and technology publishing house).
Obesity may increase the burden of the tissues and organs, the most common diseases caused by obesity is fatty liver, hyperlipidemia, hypertension, coronary heart disease, type 2 diabetes, et al. The obesity is the prevention target of many diseases; body weight control is also for diabetes early prevention.
The risk of hypertension, hyperlipidemia is much higher in obese patients than those with normal body weight, and hypertension, hyperlipidemia is the important cause leading to arteriosclerosis, so the prevalence of coronary heart disease (CHD) is raised by obesity. As the excess energy intake are converted into fatty acids, the fatty acid is transported to the liver overmuch; the overdose fatty acid can't be digested by the liver cells, then cause fatty infiltration of liver cell, finally lead to fatty liver. Severe fatty liver can be turned into liver cirrhosis.
According to the report from the American National Association of Diabetes, in the light, moderate and severe obesity, the risk of development as type 2 diabetes, respectively is 2, 5, and 10 times of the normal body weight (Xu Manyin editor, diabetes, second edition, Shanghai science and technology publishing house).
The incidence of diabetes in the world has an increasing trend year by year, and diabetes has become the world's third chronic disease after tumor and cardio-cerebrovascular diseases, which cause serious damage to human health. In recent years the incidence of diabetes is higher and higher, the number of cases surged significantly. According to statistics, the morbidity in the population over 20 years old in China reached 9.7%, approaching 100 million people. The multiple system complications caused by diabetes have high mortality and morbidity, which cause serious damage to social health, result in high medical costs and heavy burden to the society. Diabetes mainly divided into two types, in type I diabetes (insulin dependent, IDDM), the insulin secretion is absolutely inadequate, exogenous insulin treatment is needed; in type II diabetes (non-insulin dependent, NIDDM), duo to the relative lack of insulin. NIDDM has the feature of fasting hyperglycemia and excessive postprandial plasma glucose levels. In NIDDM, high blood glucose, insulin resistance and insulin secretion deficiency leads to elevated blood glucose.
Diabetes treatments include insulin injected or inhaled, and oral medications; among them, oral medications include:
Sulfonylurea (e.g., tolbutamide, glyburide, glipizide, gliclazide, glimepiride and glipizide);
Glinides (e.g., repaglinide and nateglinide);
Biguanide (such as metformin and phenformin);
Insulin synergistic agent (such as rosiglitazone and pioglitazone);
Alpha glycosidase inhibitor (such as acarbose and voglibose).
In previous clinical studies, the effects of statins on diabetes is inconsistency (Swapnil N. Rajpathak et al., Statin therapy and risk of developing type 2 diabetes: a meta-analysis. Diabetes Care. 2009; 32(10): 1924-1929).
Tan et al. reported the effect of orally administrated atorvastatin on the blood glucose in type 2 diabetes. All the patients are treated with conventional antidiabetic, the experimental group is supplemented with atorvastatin 10 mg/d for 16 weeks, the results showed that the blood glucose in the atorvastatin group is much better than the control group.
Michiro, Ishikawa, et al. reported that in oral pravastatin and atorvastatin in non-diabetic patients with hypercholesterolemia trials found that oral pravastatin is good for glucose metabolism, and atorvastatin is opposite (DOI: 10.2169/internal medicine.45.1476). Jun Sasaki reviewed the impact of statins on diabetes mellitus and glucose metabolism, and describes that, orally adiministrated pravastatin is favourable on sugar metabolism, atorvastatin (10 mg/day) and simvastatin (40 mg/day) has no effect on diabetes. But orally administrated pravastatin and high dose atorvastatin (80 mg) is detrimental on glucose metabolism (Sasaki J1, Iwashita M, Kono S. Statins: beneficial or adverse for glucose metabolism. J Atheroscler Thromb. 2006 June; 13(3):123-9.).
But there are also large amount of clinical data showing that, taking statins increase the incidence of diabetes. Some clinical meta-analysis reported that statins would reduce cardiovascular events, but will slightly increase the risk of diabetes (Statins and risk of incident diabetes: a collaborative meta-analysis of randomised statin trials. Lancet. 2010; 375(9716): 735-742), (Risk of incident diabetes with intensive-dose compared with moderate-dose statin therapy: a meta-analysis. JAMA. 2011; 305(24): 2556-2564.).
Hertension, hyperlipidemia, diabetes and obesity are all important cause of atherosclerosis, which caused great harm of cardiocerebrovascular events. So the lipid-lowering and antihypertensive treatment is important strategy to prevent cardiovascular events, respectively.
But without exception, these reports conclude that all are based on daily oral statins. Statins act as lipid-lowering, inhibiting the key enzyme (HMG-CoA reductase) used to lower cholesterol, are now in safe clinical application for decades, but it need daily use for a long-term.